Gas electric vehicle



April 27, 1937. M. ARL-:NDT

GAS ELECTRIC VEHICLE Original Filed Oct. 17, 1921 ATTORNEY Patented Apr.27, 1937` UNITED STATES PATENT OFFICE Continuation of application SerialNo. 508,191,

October i'i, 192i.

This application December 17, 1929, Serial No. 414,776. Renewed August imaints.

This invention relates to self-charging electric vehicles of the type inwhich the electric power which drives the vehicle is derived from agenerator driven by an internal combustion engine or other suitableprime mover carried by the` vehicle and delivering its output in parttothe driving motork or motors of the vehicle and in part to a storagebattery, which latter in turn supplies current to the driving motors mwhen the power demands of the vehicle exceed the generatorcutput. Theinvention of this application is an improvement on the inventiondisclosed in application Ser. No. 397,076, died jointly by myself and W.B. Morton on July 17,

This application is a continuation of my earlier filed application Ser.No. 508,191, led October 17, 1921. This application is also acontinuation'in part of my prior application Ser. No. 659,390,

filed August 25, 1923 (now U. S. Patent No.

y 1,790,634, granted January 27, 1931).

In these prior applications there is disclosed as one feature oi theinvention a so-called watt motor whereby the field characteristics ofthe generator are altered with changes in load on the driving motors ofthe system to thereby maintain a substantially constant watt output oithe generator. By this arrangement the fall in voltage incidental to thehigh rate of discharge ci the battery on heavy loads is in a measurecompensated for by the increased current output of the generator. Thisfeature of the invention of my application Ser. No. 508,191 is claimedin my later application Ser. No. 659,300 and this ap plication is led toprotect such features of the invention of my earlier application as arenot described and claimed in the later filed set of applications.

In systems of this kind when applied to the 4p propulsion of motorvehicles it is essential that the weight of the engine, generatorgandbattery be reduced to the minimum possible which will operate thevehicle in the manner desired. The generator and engine must have acapacity such that their continuous operation at maximum output over aperiod of operation will generate Vthe total amount of power requiredfor the operation of the vehicle throughout that period. A capacity lessthan this will obviously involve drawing upon the battery for more powerthan is returned to the battery so that the vehicle cannot continue tooperate unless the battery is charged from an external source ofcurrent. A generator and engine, however, of this capacity 55 is muchsmaller than the engine and generator (Cl. 29d-17) necessary to drive avehicle of the so-called straight gas electric type wherein no batteryis employed, for the reason that in that type of vehicle the engine andgenerator must have a capacity suicient to supply the peak load re- 5quirements of the vehicle operation. It is a well known fact that theacceleration of a heavy vehicle involves an energy consumption severaltimes greater than that required to operate the vehicle along a levelhighway. Hence if the 10 power plant is of suicient capacity toaccelerate the vehicle at a rate necessary for modern traic conditions,an engine is required of a size several times larger than necessary tosupply the power required for operation over an extended period. lo

In a gas vehicle embodying a battery for supu plying current foracceleration, heavy grades and other overload conditions, a very muchsmaller engine and generator can be used, but if a battery of largecapacity is employed the advantage gg@ gained in reducing the sizeof'the engine and generator is lost, and for that reason, although suchsystems of propulsion were proposed half a century ago, they have notyet come into any extended commercial operation. 25

In order to utilize a generator as sinali as possible it is essentialthat the generator be operated at full load at all times that this ispossible, but when the battery is also of small capacity the battery isliable to be injured by a 30 continuing of the charge after the batteryis fully charged and also by being charged at too high a rate, as, forexample, when the Vehicle is stopped and no current is being consumed bythe driving motors. 35

The overcharge of the battery can be guarded against by the employmentof a stop-charge device, and in the apparatus disclosed in my originalapplication Ser. No. 508,191 there is disclosed an ampere hour meteradapted to disconnect the 4c generator and battery when the battery isfully charged, thereby preventing injurious overcharge should thecurrent consumption over a more or less extended period be below theaverage. In order, however, to prevent an excessive drain 45 of currentfrom the battery should the operation of the stop-charge device beimmediately followed by a condition of overload (as is often the case invehicle operation where the overcharge is liable to take place when thevehicle is stopped in trafila, followed by overload from rapidacceleration) means are provided for starting the engine and generatoras soon as a small amount of current is drawn from the battery. By thisarrangement in the usual and expected operation of the vehicle thegenerator will be delivering its full output and the battery will beconnected in the circuit so as to receive the surplus current unlessconditions are such that that surplus would cause injury to the battery.`For preventing injury to the battery from an excessive rate o! chargethere is provided an engine and generator control for automaticallyreducing the generator output when the vehicle is stopped to therebyprevent the battery being charged at an excessive rateL when the entiregenerator output is being taken by the battery.

The accompanying drawing illustrates my improvements' diagrammatically.

Referring to the drawing, I indicates the internal combustion enginewhich may be a simple two-cylinder engine which, for a vehicle oi fivetons capacity, will produce about twelve or fteen horse-power whenoperatingv at its speed of maximum eiliciency. Directly driven from themotor I is a generator 2 governed by a control unit 3 constituting theso-called watt motor, Which is claimed in my co-pending application Ser.No. 659,300, but which is hereinafter described in some detail in orderthat the operation of the system may be fully understood. By theoperation of this unit the generator maintains a constant power out-putregardless of variations in the voltage or currents, the current beingsupplied through the mains 4 and 5 and through the motor controller 6 tothe driving motors A and a. I have illustrated two motors, but it is tobe understood that one motor, driving the vehicle through a differentialmay be used. 'I'he storage battery I0 is connected to the mains 4 and 5in parallel with the motors, the connections including the master switchor key 1, an ampere hour meter II installed between the main 4 and thebattery I0 and an automatic switch I2, the operation of which will belater described.

In the drawing I have illustrated the connections from the circuit fordriving the vehicle in heavy lines, and the connections which form partof the control only, such as the circuits of the starting devices andmotor control circuits, in light lines. In starting the car the currentfrom the battery is utilized to operate the generator 2 as a startingmotor for the gas engine.

'I'he system is controlled primarily from the master switch 1, hereshown as a plug adapted when closed to connect three contacts I3, I4 andI5, respectively, contact I4 forming the terminal of the engine startingcontrol circuit while contact I5 is connected to the main 5 between thegenerator and the motor through the speed controller 6, and the contactI8 constitutes the terminal oi a conductor I5 leading to one pole of thebattery. The other pole of the battery is connected through the amperehour meter to the main 4 by a conductor I1. A line I8 leads from themain 4 to one terminal of the automatic switch I2, which line isconnected through the switchl to the coil of a starting switch I9,designed, when the coil is energized, to close a gap between twocontacts 2I in the main 5 leading to the generator.

When the circuit is open at the plug 1, the switch I2 is held by itsspring in position to close the connection between the lines I8 and theswitch I9, the return line 22 from the switch I9 leading to the contactI4, but when the plug 1 closes the gap between contacts' I3 and I4 'acomplete circuit is formed through the conductor I6, battery I0, linesI1 and I8, and the coil oi' the starting switch I9.

When the switch I9 closes the gap between the contacts 2l the circuit iscompleted through the battery I0, line I1, main 4, generator 2, main l,contacts I5 and I2, and line I5 leading back to the battery, so that thebattery will operate the generator as a motor, thereby turning thecrankshaft of the engine I. Upon initially closing the switch I9, thecurrent passes through a resistance 28. which is cut out by automaticswitch 25 in the usual manner, followed by the closing of switch 21which completes a circuit through a shunt 5a around the resistances andremains closed so long as the generator is in operation. There may o1'course be only one starting switch or a plurality of successivelyoperating resistances 28 and switches 25 if desired.

A circuit breaker 20 of ordinary construction is installed in the line22 with its coil energized through the main 5 so that the generator iscut out and the engine will be stopped upon excessive load coming on thegenerator. The ignition apparatus of the engine, here shown ascomprising an interrupter 28 and distributor 29, is connected to thecircuit through one of the contacts 2I to be energized upon the closingof the switch Il, so that as soon as the generator is started as a motorfrom the battery, the gas engine will be put in operation.

The watt motor" comprises an armature 55 having a winding of many turnsand a commutator in a shunt 5I across the brushes of the generator 2, oracross the battery terminals as may be desired, the generator being anordinary shunt wound generator. A resistance 52 which is vadjustable invalue is provided in the shunt circuit 5I in series with the armature ofthe watt-motor. Slight variations of this resistance produces a conversechange in regulated output. A further purpose of resistance 52 will bedescribed later. The field frame 54 oi the watt motor hasa winding of a'few turns of heavy wire in series with the generator mains.

The shaft of t-he watt motor carries an arm 55 whose movement is limitedby two stops 55 to a partial revolution commensurate in extent to thelength of a series oi contacts of a rheostat 51, the contacts beingarranged to be successively engaged by a brush carried by the arm 55, soas to increase the resistance in the circuit 58 of the rheostat as thearm moves in the direction of rotation of the armature when the wattmotor is energized by the current and voltage from the generator 2.

A spiral spring 59 is attached to the armature shaft, the spring tendingto move the arm in the opposite direction to the movement produced bythe current and voltage from the generator. 'I'he spring 59 is under aninitial tension such as to produce a torque on the armature shaft equalto the torque produced by the watt motor when energized by apredetermined generator output of the desired value, the spring beingdesigned so that its tension is not materially increased by the movementof the arm; The circuit 58 of the rheostat is connected in series withthe ileld windings of the generator 2.

Conductors 6I lead from opposite ends o! the resistance 52 to the motorcontroller v5 to be connected by a contact I when the controller handleis in the stop position in which the driving motors are disconnectedfrom the circuit, thereby short-circuiting the resistance 52 in thatposition but connecting the resistance in the watt motor circuit in allpositions of the controller in which the driving motors'are energized,for a. purpose to be later described.

'Ihe operation of the watt motor will now be described. The torque onthe watt motor shaft is equal to the product of the current through thewinding of the armature 50, which varies with the voltage across thebrushes of the generator 2, and the flux across the field which varieswith the current output of the generator. When the generator 2 isoperating at its normal voltage, that is, when the generatoroutputexceeds the demands of the driving motors and a portion of the currentdeveloped by the generator is charging the battery, the torqueof thewatt motor shaft will exceed the torque of the spring 59 and the arm 55vof the watt motor will be held in a position to maintain a portion ofthe resistance of'the rheostat 5| in the circuit, therebyr giving apredetermined value to the current and watt output of the generator.When, however, an excess load comes on the driving motors, requiring aconsiderable discharge from the battery, the potential difference acrossthe mains e and 9i will fall, with the result that the output from thegenerator would decrease proportionately were it not compensated for bythe action of the watt motor. However, the decrease in voltage acrossthe ter-a minals of the generator causes a decrease in torque of thearmature of the watt motor, with the result that the coiled spring 59tends to draw the rheostat arm toward the right as shown in the drawing(that is, counterclockwise) thereby reducing the resistance in the rleldof the generator with a. corresponding increase in the current output atthe same speed of operation. The increase in current output will exactlycompensate for the decreasein voltage by reason of the fact that thewinding oi' the field frame of the watt motor is in series with the main5 and therefore the torque oi the watt motor arm will loe increased withthe increase in current offsetting and balancing the action of thespring 59 when the rlieostat arm reaches a position where the increasein current has oiTset the decrease in volt age.

es the speed. of the gas engine at a xed throttie position isvdirectlyproportional to the load on the engine shaft, the engine will operate atall times at a constant speed regardless or the position or the arm 55of the rheostat. Hence, the engine will at all times operate at thespeed ci" inaninuun eciency.

By having a large number of coils to the rheo stat the variation in loadon the engine can he reduced to almost nothing. However, in practicesuch minute regulation is not essential and a rheostat allowing avariation in speed oi? 5% either way from the best speed of operation isnot material.

The watt motor also prevents the generator loeoorning overloaded,thereby tending to stall the engine. If we assume the battery andgenerator worlnng in parallel in driving the truck under more thannormal load any increase in the load from a grade or road conditionswill call for an increased current from the generator as well as fromthe battery. Such increased current, however, flowing through the mainEi will increase the torque of the watt motor shaft, thereby shiftingthe rheostat arm further to the left until the power output againbalances the pull oi the spring. By this system the extra load mustaiways be taken by the battery, regardless oi the cause of nature of thevariation.

I have shown for the drivers control of the vehicle a standardcontroller such as now employed for electrically propelled vehicles,and.

f have combined with it an engine control and a that thereafter as thecontrol handle ls turned the fields will be connected in parallel andthe armatures in series and upon the nal adjustment, the elds andarmatures will both be in parallel, as is usual in this type of control.

I will not describe the motor control circuit in detail as l claim noparticular novelty or advantage in the arrangement shown. The `samepurpose may be obtained by a single motor with double windings and invarious other ways now in use. For convenience in reading the drawing, Inave designated the leads from the eld F of the motor A, FU and PL2respectively, and the leads from the armature of the motor A, All.,1 andAL2, respectively. l have also designated the leads from the field f ofthe motor a, fil and ft2, respectively, and the leads from the armatureoi the motor a, all and cl2, respectively.

The controller drum has eleven contact strips which l have indicatedI-m, inclusive. Contact li comprises a short segment which in the stopposition or the controller illustrated ln the drawing short circuits theresistance 52 in the line 5i to one brush of the watt motor ar1na= ture.The purpose of this resistance is to cause a dierent setting of the wattmotor arm when the motor is in operation.

This short segment moves od its contacts as next operating position theresistance R1 will be out out and upon further adjustment of the controlhandle the connections will be changed from series to parallelarrangement, as described.

i have also shown the controller as provided with an auxiliary drum 62carrying reversing connections, the aurdliary drum being operated by thereversing handle 53 passing through the hollov.1 shaft or the maindrumv. The reversing drum operates to reverse the direction of flow orcurrent through the armatures of the motor and thereby vreverse thedirection of drive.

l have also shown the control drum as provided with an enginecontrolling mechanism whereby the throttle of the engine indicateddiagrammatically at l2 will be partially closed when the controller armis at the stop position. This mechanism comprises a cam 64 attached tothe bottom end of the drum E and having an inclined cam on its lowerface, which cam works against one arm of a bell crank 65 connectedthrough a link to a lever 66 fulcrumed at 6l, the free end of the lever66 being held by a spring 58 in a direction to press the arm of the bellcrank i5 against the cam.

is then to hold the generator this reduced value.

Also carried by the pivot 01 oi' the lever it is an arm 69 which extendsalongside the lower end of the'lever 6C to a point below the end, of thelever. The arm 8S is connected to the lower end of the lever to move in`synchronism with it under normal conditions by means of two springs 1lwhich lie on either side oi the lever ,their outer ends abutting againststops carried by the arm 69. By this arrangement the arm i! may beoperated independently of the lever 66 by applying to it a pressureexceeding the tension of the spring 10 but when free to move will movein synchronism with the lever. of the arm 69 is connected through a rod1I with the bell crank 12 which controls the movement of the throttle,the arrangement being such that the movement of the lever 66 through theaction of the cam 64 tends to close the throttle while the movementunder the action of the spring i8 opens the throttle. The arm $9 may beindependently operated by the driver through any suitable connection,for instance, the treadle lever 13, in the manner shown. No operation ofthe lever 13 is required in the normal working of the control system,but it is desirable to provide this independent control so that in caseoi any breakdown of the control system the engine may be regulated tomeet the emergency condition.

'I'he purpose oi partially closing the throttle when the vehicle is notin operation is to alter the characteristics oi the engine and thegenerator so as to avoid charging the battery at a rate suillcientlyhigh to be harmful. When the control arm is in stop" position thecontact segment 6 connects theV leads il from the resistance 52, therebyshort-circuiting the resistance and increasing the current across thebrushes rof the armature of the watt motor. The torque on the watt motorarm will thereby be greater for the same energy out-put of thegenerator, with the result that the watt motor arm would be shiftedacross the rheostat against the tension of its spring Il, and unless therheostat was oi wide range the arm would be shifted through the entireextent oi its movement against the stop pin li and held there so long asthe resistance 52 was cut out, thereby cutting out the automatic controloi' the generator altogether when the vehicle is stopped. If, however,the resistance 51 has suillcient range, the generator watt output can bereduced in direct proportion to the decrease oi resistance oi the wattmotor armature circuit, when resistance 52 is short-circulted by contactC. 'I'he action oi the watt motor regulator output constant at By meansof the above described throttle control the power output oi the enginefor a predetermined speed is reduced to an extent corresponding with theincrease in torque of the watt motor represented by the resistance l2,thereby reducing the total generator output such that the greaterproportional torque oi the watt motor arm when the resistance is cut outmakes the actual torque on the watt motor arm the same as when theresistance l2v is in the circuit and the engine is operating to its fullcapacity. The rheostat I1 thus becomes eiiective when the generator isoperating at its reduced or battery-charging output, and causes thecurrent output of the generator to decrease when the voltage rises asthe battery nears full charge, thereby attaining the taper charge eiiectmon desirable for the battery.

I have shown my automatic control system asv comprising, the ampere hourmeter il controllingl The lower end V both the starting and stopping oithe engine in the manner described above. This mechanism comprises anampere hour meter of ordinary construction but provided with two sets ofcontacts. 'one set closed by the hand of the ampere hour meter when thebattery is fully charged, thereby closing the circuit through a coil Ilthe energization oi which opens the starting switch circuit at i2 andcauses the control switches Il, 25 and 21 to open, which brings theengine to stop. When the starting switch is opened by the coil l0 itwill be held open by a trip Il so that the switch will not close whenthel circuit through the coil is broken by a slight discharge of thebattery. 'Ihe other pair oi contacts of the ampere hour meter control isa circuit through a coil 82 which operates the trip Il to release thetrip and allow the switch i2 to close when the battery is discharged apredetermined amount. which may be a third, or a quarter, oi itscapacity.

It will of course be understood that the contacts l2 and 8l areconnected as shown to one side of the battery III and that the othercontacts are connected through the coils 0l and t2, respectively, to theother side oi the battery.

'I'he contacts controlling the coil l2 may be adjustable with referenceto the path oi movement of the index hand oi the ampere hour meter tovary the extent ot discharge allowed before the engine is again started.

In the operation of the apparatus the contacts 8l are set to restart theengine after a minor portion only of the current stored in the batteryhas been utilized. The position oi the contacts M will be varied to someextent by the service to which the vehicle is put and should bedetermined so that the engine will be running at all times except whenthe vehicle is at rest for a substantial period of time. Ii, forexample. the vehicle was running in crowded traillc where there werefrequent stops incidental to the tra!- ilc, the contacts I4 should beset iar enough away from the contacts for the engine to continue inoperation during such stops, and thus avoid repeated starting andstopping of the engine. 0n the other hand, if the vehicle is used underconditions which permit more continuous running the contacts will be setcloser together. the intended mode oi operation in either case being tooperate the vehicle on the battery alone only enough to insure againstfrequent starting and stopping of the engine.

I claim: i

l. In an apparatusof the class described, the combination of anr`electric operating motor, a prime mover for supplying power thereto, agenerator operated by the prime mover, a storage battery, connectionsbetween the generator, storage battery, and the electric motor, wherebythe storage battery assists in driving the motor, when the load thereonexceeds a predetermined value and is charged by the generator when theload is below such value. a controller (or the system for maintaining apractically constant energy output of the generator during both saidconditions of operations, a motor ntroller and means actuated thereby toalter the setting oi the generator controller.

2. In an apparatus of theclass described. the combination of an electricoperating motor. a prime mover for supplying power thereto. a generatoroperated by the prime mover, a storage battery, connections between thegenerator, storage battery and the electric motor. whereby the stanzebatteryauim in driving the motor u when the load thereon exceeds yapredetermined value and is charged by the generator when the load isbelow such value, a controller for the system for maintaining apractically constant energy output of the generator during both saidconditions of operations, amotor controller, and means actuated therebyto alter the setting of the generator controller and engine fuel supply.

3. In an apparatus of the class described, the combination of anelectric operating motor, a prime mover for supplying power thereto, agenerator operated `by the prime mover, a storage battery, connectionsbetween the generator, storage battery, and the electric motor, wherebythe storage battery assists in driving the motor, when the load thereonexceeds a predetermined Value and is charged by the generator when theload is below such value, a controller for the operating motors andindependent means actuated by said controller for reducing the generatoroutput.

`4. In an apparatus of the class described, the combination of anelectric operating motor, a prime mover for supplying power thereto, agenerator operated by the prime mover, a storage battery, connectionsbetween the generator, storage battery, and the electric motor, wherebythe storage battery assists in driving the motor, when the load thereonexceeds a predetermined value and is charged by the generator when theload is below such value, a controller for said operating motors havingmeans for regulating the supply of current to said motors, and means forreducing the output of said generator when said motor controller isactuated to reduce the current to said operating motors to apredetermined extent.

MORTON ARENDT.

